One-pot synthesis of Schiff base-containing hyperbranched polysiloxane and its corrosion inhibition properties

Abstract

Polysiloxanes are widely used as protective barriers on metals to delay erosion/corrosion, but have been rarely used as the corrosion inhibitor. In this study, we designed a facile one-pot approach to synthesize a Schiff base hyperbranched polysiloxane (SHBPSi) based on simultaneous nucleophilic addition and hydrolytic condensation, and applied it as a corrosion inhibitor to prevent corrosion of steel in 1 M HCl aqueous solution. SHBPSi was confirmed to be an efficient corrosion inhibitor for carbon steel in the acid solution environment via electrochemical measurement. As a result of the characteristic physical and chemical adsorption, the degree of coverage of SHBPSi on the steel surface was up to 95% with an SHBPSi concentration of 100 mg L⁻¹ in acid solution. Morphological analysis revealed that SHBPSi adsorbed onto the metal surface played an essential part in controlling the surface roughness and deposition of corrosive media. SHBPSi led to a substantial enhancement in both corrosion inhibition and steady adsorption onto the steel surface in an acid environment, which could be attributed to the partial electron transfer from N atoms to the metal surface and to the formation of a metal–inhibitor complex. The hyperbranched structure helped to improve the long-term dispersion stability, as well as build the barrier network.